(Revision of ANSI/AWWA C). Copyright © This document is an American Water Works Association (AWWA) standard. It is not a. 1, , AWWA issued the updated ANSI/AWWA C 14 standard, Disinfecting Water Mains, a result of the review that AWWA standards must go through. AWWA Standard for Disinfecting Water Mains – Jun 1, – Ansi/AWWA C DS60 Water Supply Distribution Standard – Pipelines Other.
|Published (Last):||28 June 2009|
|PDF File Size:||18.99 Mb|
|ePub File Size:||2.52 Mb|
|Price:||Free* [*Free Regsitration Required]|
awwa c – Edit & Fill Out Online Templates, Download in Word & PDF |
It will be necessary to reestablish the temporary connection after completion of the hydrostatic pressure test to flush out the disinfectant water prior to final connection of the new main to the distribution system. Test results should confirm that the water quality is appropriate for distribution. The more closely the rate of delivery is correlated to the rate of pipe laying, the lower the risk of contamination. The term liquid chlorine is sometimes used to describe a hypochlorite solution. Given the often significant amount of time and materials involved in a new water main project, careful disinfection and testing of the main are reasonable and necessary to ensure public health protection.
Disinfectants other than chlorine may be appropriate to use. Specific policies of the state or local agency.
AWWA C651-14 Disinfecting Water Mains
After disinfection and final flushing such that typical system chlorine residuals are present, if the system operates with a residual, samples shall be collected as follows: Clarified differences in the requirements between new and aawwa mains foreword II. Precautions shall be taken to ensure that air pockets are eliminated. Table 4 gives the amount of chlorine required for each ft The quantity of granules at each location shall be as shown in Table 1.
Added spray disinfection method for large transmission mains Sec. Joints of pipe in the trench shall be completed before work is stopped. The flushed water should run visually clear, have a measurable chlorine residual if the system operates with a residual, and be checked with bacteriological testing.
Also, any connection of a new water main to the active distribution system before the receipt of satisfactory bacteriological samples may constitute a cross-connection. For larger mains, pigging or other suitable method acceptable to the purchaser is an option in place of high velocity flushing.
If the initial disinfection fails to produce satisfactory bacteriological results, or if other results indicate unacceptable water quality, the main may be reflushed and shall be resampled. If direction of flow is not known, samples shall be collected on either side of the repair site. Makeshift equipment is not acceptable when liquid chlorine gas cylinders are used. The latter solution requires 1 lb g of calcium hypochlorite in 8 gal The environment to which the chlorinated water is to be discharged shall be inspected.
The party that manufactures, fabricates, or produces materials or products.
Water Main Break Guidance Manual epa. Heavy particulates generally contain bacteria and prevent even very high chlorine concentrations from contacting and killing these organisms. The spray method is suitable for use in large-diameter transmission lines where spray equipment can be used to disinfect all surfaces of the pipe. Because of the differences between initial installation and repair, the disinfection requirements for each situation are also different.
For repaired mains that are maintained under pressurized conditions at all times, bacteriological testing is not required When required, samples are now specified to be collected at least 16 hr apart, or 15 min apart after awwwa hr rest period.
Nonetheless, the repair work needs to d651-05 accomplished using sanitary and safe procedures by well-trained crews with proper supervision and guidance. A supplier may or may not be the manufacturer.
It is not a specification.
AWWA C Disinfecting Water Mains
Refer to preventive and corrective measures described previously in Sec. Revisions were approved on Sept. Chlorine application shall not cease until the entire main is filled with chlorinated water. While the contact times of the methods may not be identical, the end result, absence of coliforms, is the same for all four methods. The following information should be provided by the purchaser. Calcium hypochlorite tablets 5-grams shall be placed in the upstream end of each section of pipe to be disinfected, including branch lines.
The amount of chlorine combined with ammonia NH3 or other compounds in water. To ensure that this concentration is achieved, the free chlorine concentration shall be measured at regular time intervals sufficient to guide the completion of the successful loading of the target chlorine concentration.
As chlorinated water flows past fittings and valves, related valves and hydrants shall be operated so as to disinfect appurtenances and pipe branches. In order to prevent damage to the pipe lining or to prevent corrosion damage to the pipe itself, the heavily chlorinated water shall be flushed from the main fittings, valves, and branches until chlorine measurements show that the concentration in the water leaving the main is no higher than that generally prevailing in the distribution system or that is acceptable for domestic use.
An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. Before approving a main for release, let it sit for a minimum of 16 hr without any water use. After chlorination and repair, perform scour flushing at 3. Specific situations not captured below need to be evaluated and the appropriate disinfection and sampling methods followed.
Samples for bacteriological analysis shall be collected in sterile bottles treated with sodium thiosulfate, in accordance with Section —Samples of Standard Methods for the Examination of Water and Wastewater. The interiors of pipes, fittings, and valves shall be protected from contamination. Whichever disinfectant or method is selected, approval from the local regulatory agency may be required.
Two dropping pipettes that deliver a 1-mL sample in 20 drops. This procedure must not be used on solvent-welded plastic or on screwed-joint steel pipe because of the danger of fire or explosion from the reaction of the joint compounds with the calcium hypochlorite.